The EU Machinery Regulation wants logs kept for *five years*

A five-year receipt for every change

If you've ever tried to find a receipt from two years ago, you know the problem. Now imagine the product is a robot that cuts metal, and someone needs to know which software version it was running when it injured an operator.

From 20 January 2027, the EU Machinery Regulation requires manufacturers to keep a traceable log of safety-relevant software changes, and to keep it for five years ^[1]. That's not a log you glance at during commissioning and forget. It's a log that might be opened by an investigator, a court or a notified body half a decade later, long after the people who set the machine up have moved on.

The regulation replaces the Machinery Directive 2006/42/EC and covers machines and related products placed on the market from that date ^[1]. It doesn't retroactively apply to machines already out in the field under the old directive, but anything new falls under the new rules.

What has to be logged

The regulation says safety-relevant software changes must be logged and traceable ^[1]. That means updates, patches and configuration changes that could affect how safely the machine operates. The log has to show what changed, and it has to be kept in a way that lets someone check it years later.

Machinery must also be protected against corruption ^[1]. In other words, it shouldn't be possible for someone to quietly tamper with the software or the log and have the machine carry on as though nothing happened.

For machines with self-learning behaviour, there are additional requirements ^[1]. Self-learning means the machine adapts its operation based on data it gathers while running. The regulation recognises that such machines pose different risks, because their behaviour can change without anyone issuing a software update in the traditional sense.

Five years is a long time in software

A five-year requirement changes how manufacturers have to think about record-keeping. In software development, five years can span several product generations, three or four changes of personnel and a move to a different version control system. The log that seemed easy to maintain in year one has to stay readable, traceable and trustworthy all the way to year five.

The practical question is: if a notified body or an accident investigator asked you in 2032 which version of the safety logic was running on a particular machine in 2028, could you show them? And could you show them in a way they don't have to take on trust?

What this means for you

If you manufacture or integrate machinery that will be placed on the EU market from 20 January 2027, three things are worth deciding now:

• Which changes in your software count as safety-relevant, and where will you draw that line?
• How will you log those changes in a way that stays traceable for five years, through staff changes, system migrations and everything else that happens in that time?
• How will you protect the log and the machine itself against corruption, so that an investigator can trust what they're looking at?

For machines with self-learning behaviour, the additional requirements mean you'll need to document not just deliberate updates but also how the machine's learning affects its safety functions.

Sealing software change logs

This is a strong fit for a digital witness. The thing to seal is each safety-relevant software change as it is logged: the machine identifier, the software version, what changed, who authorised it and when. You seal a fingerprint of that record, not the content itself, so the log stays in your systems.

Sealing happens at the time of the change. If an investigator, a notified body or a court asks five years later what version was running on a given date, anyone you share the log with can check that it matches the fingerprint sealed at the time. Change one character in the log and the fingerprint won't match.

What a digital witness shows is that the log record hasn't changed since it was sealed, even if someone with administrator rights tried. What it doesn't show is that the change itself was safe, properly tested or compliant with the regulation. It gives you a checkable record; it doesn't replace your safety assessment.

You can seal records through WitniumChain's REST API, SDK or MCP server. The content never leaves your systems. The first 2,000 witnesses a month are free. Read the docs to see how it works in a build or deployment pipeline.

How it would work

1. Each time a safety-relevant software change is made, your system logs it and sends a fingerprint to WitniumChain.
2. The fingerprint is sealed on a chain where any later change would show, and you get a witness ID back.
3. Five years later, if someone asks, you calculate the fingerprint of your log record again and check it against the sealed one. If it matches, the record is unchanged.

What to watch

20 January 2027 is the date the regulation starts to apply ^[1]. Between now and then, manufacturers will need to decide how to implement the logging and traceability requirements in practice, and national market surveillance authorities will clarify how they intend to enforce them.

For machines already on the market under the Machinery Directive, the new regulation doesn't apply retroactively ^[1]. But for anything placed on the market from 20 January 2027, the five-year logging requirement will be in force from day one.